You need two cables for that you will most likely have. You need a 4-pin power connector for power most likely and a data cable.
There are two types of data cables, SATA and some other old one which I will refer to as "ribbon cable". You need to figure out which one data cable...
This is a SATA data cable. This is newer technology for computers, if you have an old computer, doubt you have this.
This is the old fashioned 26-pin data "ribbon cable". I think you will probably have this.
This is a 4-pin power connector cable. Self explanatory.Now that you have this information, you can figure out which of the data cables you have. You can do this by simply opening up your computer and looking. You probably won't need to buy cables as all computers come with extra 4-pin power connectors and data cables for adding an extra Hardrive or optical drive.
Once you get your hardware hooked up, you can go to your BIOS, set primary hardrives and secondary hardrives, but that won't be necessary until you get your hardrive hooked up. Plus, there are tons of guides out there teaching you how to partition and put your drives in different RAID arrays.